<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <style>
    *{
      margin: 0;
      padding: 0;
      list-style: none;
    }
    html,body{
      background-color: #ccc;
    }
    .box{
      width: 500px;
      margin: 30px;
    }
    ul{
      overflow: hidden;
    }
    .picgroup li{
      width: 20%;
      margin-right: 20px;
      float: left;
    }
    li img{
     width: 100%;
    }
    .show{
      width: 90%;
    }
    .show img{
      width: 100%;
    }
  </style>
</head>
<body>
  <div class="box">
    <h1>美女画廊</h1>
    <div class="picgroup">
      <ul>
        <li><img src="images/1-small.jpg" alt="美女A"></li>
        <li><img src="images/2-small.jpg" alt="美女B"></li>
        <li><img src="images/3-small.jpg" alt="美女C"></li>
        <li><img src="images/4-small.jpg" alt="美女D"></li>
      </ul>
      <div class="show"><img src="images/placeholder.png" alt=""></div>
      <span>选择一个图片</span>
    </div>
  </div>
  <script src="../../jquery-1.12.4.min.js"></script>
  <script>
    $('li>img').click(function(){
      $('.show img').prop('src',$(this).prop('src'));
      $('span').text($(this).prop('alt'))
    })
  </script>
</body>
</html>